The function of RABGGTA (Rab geranylgeranyltransferase subunit alpha, ENSG00000100949) is as follows. Catalyzes the transfer of a geranylgeranyl moiety from geranylgeranyl diphosphate to both cysteines of Rab proteins with the C-terminal sequence -XXCC, -XCXC and -CCXX, such as RAB1A, RAB3A, RAB5A and RAB7A. .